The present invention is directed to a stage assembly for moving a device. More specifically, the present invention is directed to a stage assembly including a damping assembly for an exposure apparatus.
Exposure apparatuses are commonly used to transfer images from a reticle onto a semiconductor wafer during semiconductor processing. A typical exposure apparatus includes an illumination source, a reticle stage assembly that retains a reticle, a lens assembly and a wafer stage assembly that retains a semiconductor wafer. The reticle stage assembly and the wafer stage assembly are supported above a ground with an apparatus frame.
Typically, the wafer stage assembly includes a wafer stage base, a wafer stage, a wafer table that retains the wafer, and a wafer stage mover assembly that precisely positions the wafer stage, the wafer table and the wafer. Additionally, the wafer stage assembly can include a table mover assembly that moves the wafer table relative to the wafer stage. Somewhat similarly, the reticle stage assembly includes a reticle stage base, a reticle stage that retains the reticle, and a reticle stage mover assembly that precisely positions the reticle stage and the reticle. The size of the images transferred onto the wafer from the reticle is extremely small. Accordingly, the precise relative positioning of the wafer and the reticle is critical to the manufacturing of high density, semiconductor wafers.
Unfortunately, the wafer stage mover assembly and the table mover assembly generate reaction forces and disturbances that can vibrate the wafer stage base and the apparatus frame. The vibration influences the position of the wafer stage base, the wafer stage, the wafer table, and the wafer. As a result thereof, the vibration can cause an alignment error between the reticle and the wafer. This reduces the accuracy of positioning of the wafer relative to the reticle and degrades the accuracy of the exposure apparatus.
In light of the above, there is a need for a stage assembly that precisely positions a device. Additionally, there is a need for a stage assembly that reduces the influence of reaction forces from the table mover assembly upon the position of the wafer table, the wafer stage, the wafer stage base, and the apparatus frame. Moreover, there is a need for an exposure apparatus capable of manufacturing precision devices such as high density, semiconductor wafers.
The present invention is directed to a stage assembly for moving a device relative to a stage base. The stage assembly includes a stage, a mover assembly, a device table, and a damping assembly. The mover assembly includes a stage mover assembly and a table mover assembly. The stage mover assembly is connected to the stage and moves the stage relative to the stage base. The device table retains the device. The table mover assembly is connected to the device table and moves the device table relative to the stage. The damping assembly is coupled to the mover assembly.
A number of embodiments of the stage assembly are provided herein. In one or more of these embodiments, the damping assembly reduces the reaction forces and disturbances created by the mover assembly that are transferred to the stage and the stage base. As a result thereof, the stage assembly can more accurately position the device. Further, the stage assembly can be used in an exposure apparatus to manufacture high density, high quality semiconductor wafers.
As provided herein, the table mover assembly moves the device table with at least one degree of freedom and more preferably at least three degree of freedom relative to the stage. For example, the table mover assembly can include a vertical mover assembly that moves the device table relative to the stage along a Z axis, about an X axis and about a Y axis relative to the stage. In this embodiment, the vertical mover assembly is coupled to the damping assembly so that the damping assembly reduces the reaction forces that are transferred to the stage and the stage base along the Z axis, about the X axis and about the Y axis.
Further, the table mover assembly can move the device table with six degrees of freedom relative to the stage. In this embodiment, the table mover assembly includes a horizontal mover assembly that moves the device table relative to the stage and the stage base along the X axis, along the Y axis and about the Z axis.
In the embodiments provided herein, the damping assembly includes a Z reaction mass and a mass guide. The table mover assembly is coupled to the Z reaction mass and the mass guide connects the Z reaction mass to the stage. With this design, the Z reaction mass moves relative to the stage and the stage base with at least one degree of freedom and more preferably three degrees of freedom. In one embodiment, the mass guide is a flexible connector that allows for motion of the Z reaction mass along the Z axis, about the X axis and about the Y axis and inhibits motion of the Z reaction mass along the X axis, along the Y axis and about the Z axis relative to the stage and the stage base.
In yet another embodiment of the present invention, the mover assembly moves the device table relative to the stage base with at least four degrees of freedom and more preferably at least six degrees of freedom. In this embodiment, the damping assembly is coupled to the mover assembly and reduces the reaction forces that are transferred to the stage base with at least four degrees of freedom and more preferably at least six degrees of freedom.
The present invention is also directed to an exposure apparatus, a device made with the exposure apparatus, a wafer made with the exposure apparatus, a method for making a stage assembly, a method for making an exposure apparatus, a method for making a device and a method for manufacturing a wafer.